Fig. 1

Schematic picture overviewing metabolic pathways in Thermoanaerobacterium AK17. The pathways for production of ethanol, acetate, lactate and butyrate in Thermoanaerobacterium AK17 are shown. Positions in the pathways where genes have been deleted are indicated by crosses (red cross: ldh knockout; green cross: ack/pta knockout; yellow cross: bk/ptb knockout) and the designations of the corresponding engineered strains are shown in the box in the upper right corner. The enzymes responsible for different steps in the pathways are indicated by letters (a–j) in the pathways, and the corresponding enzymes are shown in the explanatory box in the lower left corner of the figure